The present invention relates to windscreen wipers for vehicles and in particular to windscreen wipers of the kind in which a wiper blade is mounted upon an arm for reciprocal pivotal movement over the windscreen.
With simple wiper mechanisms of the this type, the wiper blade sweeps an arcuate path over the windscreen which provides limited coverage of the windscreen. Such wipers are normally used in pairs, the arcuate paths of which overlap to provide adequate coverage of the windscreen. With the shape of windscreens on modern vehicles and also to reduce the complexity of the drive mechanism, there has been a tendency on modern vehicles to adopt single wiper systems. However, in order to improve the area of windscreen covered by such systems, it has been proposed to modify the arcuate path of the wiper blade by extending the arm axially as it pivots. However, in the systems proposed hitherto, a separate drive means or complex mechanical linkage has been required, in order to provide axial movement of the arm.